Area Forecast Discussion
Issued by NWS Upton, NY-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 231722
Area Forecast Discussion
National Weather Service New York NY
122 PM EDT Sun Oct 23 2016
Low pressure over southeastern Canada will gradually weaken over
the next couple of days, while a clipper low and its associated
cold front move through the area early Monday morning. High
pressure builds across the area Tuesday and Wednesday, followed by
a Pacific frontal system at the end of the week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Mixing well and higher winds have been making it down to the
surface with peak wind gusts around 32 KTS. With the mixing dew
points across the interior have lowered into the lower and mid
20s. Updated for temperatures, dew points, and winds across the
Surface low pressure centered near the St Lawrence river will
meander across southeastern Canada through today and into tonight
as the upper closed low and negative trough remain across eastern
Canada. With a well mixed boundary layer across the region
temperatures will be fairly uniform...upper 50s to lower 60s.
Drier air and weak subsidence will keep area cloud free until
later this afternoon as clouds approach ahead of a shortwave
moving through the northern stream.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Northern stream shortwave moves quickly east tonight and passes
through the area after midnight. Decent lift along and ahead of
the associated mid level short wave will result in a brief period
of rain with up to a quarter inch possible. Most locations will
dry out by daybreak Monday with the possible exception of far
eastern LI and SE CT.
Cold advection will follow through the day Monday with another
shot of cold air following a short wave trough Monday evening.
Amplifying upper ridge over the western U.S. ahead of the next
Pacific storm system will help to amplify the downstream trough
across eastern Canada and the northeast. In addition, an upstream
block resides across the central Atlantic. This will result in a
deep-layered NW flow across the area with a shot of unseasonably
cold air to arrive Monday night and persist into mid week.
Gusty northwest winds will continue during this time with weakening
low pressure over eastern Canada and polar high pressure building
southeast from central Canada.
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Upper trough remains across the northeastern portion of the country
early to mid week, as ridge to the west eventually flattens per
global models. Differences arrive with handling of shortwave that
develops across the upper mid west as it traverses east late in the
At the surface, low pressure associated with lingering upper trough
moves slowly across eastern Canada, as high pressure builds out of
central Canada and into the Great Lakes Region through mid week. The
high briefly slides across the area Thursday before giving way to
low pressure Thursday and Friday. Frontal boundaries, first warm
front followed by the cold front, impact the area from late
Thursday, into Friday. For Saturday, forecast becomes less clear. A
possible weak frontal boundary may move through Saturday, but
confidence in this remains low at this time.
Generally dry conditions are anticipated through Wednesday night
as high pressure slowly builds. Cyclonic flow could result in
more cloud cover each day, especially into New England Tuesday and
The best chance for rain looks to be late Thursday, Thursday night
into Friday. ECMWF slower with upstream system compared to usually
Temperatures will be below normal Tuesday and Wednesday, then slowly
moderate closer to normal Thursday through Saturday.
.AVIATION /18Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --High pressure builds to the south today with strong low pressure
over eastern Canada. A cold front moves through late tonight into
WNW winds gusting 25 to 30 kt, expected through around 21z. An
isolated peak gust up to 35 kt cannot be ruled out. Gusts will end
this evening. Winds decrease and gusts end this evening. Winds
will back to the SW overnight, generally around 7-10 kt. After the
cold front passage early Monday, winds will shift to the NW and
increase with gusts 20-25 kt by late morning.
VFR through the TAF period. There is a low chance for MVFR in
light rain late tonight into early monday morning.
.Outlook for 18Z Monday through Friday...
.Monday Afternoon-Monday Evening...VFR. NW winds G20-25 kt.
.Tuesday...VFR. NW winds G25-30 kt, diminishing Tuesday night.
.Wednesday...VFR. NW-NNW G20 kt possible near the coast.
.Thursday-Friday...MVFR or lower possible late Thursday into
Friday in showers.
-- End Changed Discussion --
Winds and gusts have diminished to below gale except across the
eastern ocean waters east of Moriches Inlet...ANZ350. Wind gusts
at small craft levels through this afternoon on the remainder of
the waters, and on the ocean waters into Monday night with the
passage of another cold front late tonight into early Monday as
northwesterly winds will gust to small craft levels. There will be
a lull in the winds late tonight and the surface low and front
move through as the surface pressure gradient weakens. However
seas on the ocean waters remain at small craft levels.
Kept the gale warning for east of Moriches inlet through today.
This may be changed to a small craft with the afternoon package if
wind gusts continue downward trend.
The gale warning was downgraded to a small craft through today on
the Long Island sound, the Long Island bays, and New York Harbor.
Finally, the gale warning was downgraded to a small craft advisory
on the ocean waters west of Moriches Inlet through Monday night.
Small craft conditions on the ocean waters are possible through
Tuesday. Winds diminish again with a more substantial decrease of
the pressure gradient Tuesday night with a Canadian high
approaching. High pressure remains across the waters through early
Up to a quarter inch of rain is possible tonight with a fast
moving area of low pressure. Rainfall of 1/2 inch or more is
possible Thursday into Friday. No hydrologic impacts are
MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ330-
Small Craft Advisory until 6 AM EDT Tuesday for ANZ353-355.
Gale Warning until 6 PM EDT this evening for ANZ350.